47° FLOWERS OF FIELD, HILL, AND SWAMP 



2. North American Papaw 



AsJmina triloba. — Family, Custard-apple. Color, dull pur- 

 ple. Leaves, alternate, thin, inversely ovate to lance-shaped, 

 entire, acute, feather-veined, with a disagreeable odor when 

 crushed. Time, April and May. 



Calyx, of 3 sepals. Petals, thick, 6, in 2 irows, the outer 

 ones much longer than the sepals, i-J inches across. Stamens, 

 many, crowded together. Pistils, few. Flowers, single, from 

 the axils of last year's leaves. Fruit, yellowish, 3 to 4 inches 

 long, looking like a small banana, ripe in autumn, sweetish and 

 edible. Stems of the young shoots softly downy, becoming, 

 later, smooth. 



A shrub or small tree, from 10 to 20 feet high, growing on the 

 banks of rivers, from western New York to Pennsylvania, Illinois, 

 and southward. The family is represented by many species in 

 the tropics. 



3. Common Barberry 



Birberis vulgaris. — Family, Barberry. Color, yellow. 

 Leaves, alternate, inversely ovate, in tufts, springing some- 

 times from the axils of spines. From the centre of the rosette 

 of leaves racemes of flowers spring. Time, May and June. 



Sepals a.nd petals, 6. Bractlets below the sepals. Stamens, 6. 

 Pistil, I. Fruit, a long, acid berry, containing one or two hard 

 seeds. They are often preserved, and make a refreshing drink. 



The stamens are curiously sensitive. Kolreuter was the first to 

 discover the fact that when the filaments are touched, the anthers 

 bend towards the pistil and come in contact with its stigma, 

 straightening up again soon after. This phenomenon is best seen 

 in dry weather. It is a device to secure cross-fertilization, a visit 

 from an insect causing the anthers to shed their pollen upon its 

 body, to be borne to another flower. The barberry is supposed to 

 be injurious to wheat, being invested with a mildew (Acidium ber- 

 beridis), which in a different form becomes the rust {(/redo) of 



